/* ===========================================================
 * JFreeChart : a free chart library for the Java(tm) platform
 * ===========================================================
 *
 * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
 *
 * Project Info:  http://www.jfree.org/jfreechart/index.html
 *
 * This library is free software; you can redistribute it and/or modify it 
 * under the terms of the GNU Lesser General Public License as published by 
 * the Free Software Foundation; either version 2.1 of the License, or 
 * (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but 
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, 
 * USA.  
 *
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
 * in the United States and other countries.]
 *
 * --------------
 * PiePlot3D.java
 * --------------
 * (C) Copyright 2000-2005, by Object Refinery and Contributors.
 *
 * Original Author:  Tomer Peretz;
 * Contributor(s):   Richard Atkinson;
 *                   David Gilbert (for Object Refinery Limited);
 *                   Xun Kang;
 *                   Christian W. Zuckschwerdt;
 *                   Arnaud Lelievre;
 *                   Dave Crane;
 *
 * $Id: PiePlot3D.java,v 1.10.2.2 2005/10/25 20:52:08 mungady Exp $
 *
 * Changes
 * -------
 * 21-Jun-2002 : Version 1;
 * 31-Jul-2002 : Modified to use startAngle and direction, drawing modified so 
 *               that charts render with foreground alpha < 1.0 (DG);
 * 05-Aug-2002 : Small modification to draw method to support URLs for HTML 
 *               image maps (RA);
 * 26-Sep-2002 : Fixed errors reported by Checkstyle (DG);
 * 18-Oct-2002 : Added drawing bug fix sent in by Xun Kang, and made a couple 
 *               of other related fixes (DG);
 * 30-Oct-2002 : Changed the PieDataset interface. Fixed another drawing 
 *               bug (DG);
 * 12-Nov-2002 : Fixed null pointer exception for zero or negative values (DG);
 * 07-Mar-2003 : Modified to pass pieIndex on to PieSectionEntity (DG);
 * 21-Mar-2003 : Added workaround for bug id 620031 (DG);
 * 26-Mar-2003 : Implemented Serializable (DG);
 * 30-Jul-2003 : Modified entity constructor (CZ);
 * 29-Aug-2003 : Small changes for API updates in PiePlot class (DG);
 * 02-Sep-2003 : Fixed bug where the 'no data' message is not displayed (DG);
 * 08-Sep-2003 : Added internationalization via use of properties 
 *               resourceBundle (RFE 690236) (AL); 
 * 29-Oct-2003 : Added workaround for font alignment in PDF output (DG);
 * 20-Nov-2003 : Fixed bug 845289 (sides not showing) (DG);
 * 25-Nov-2003 : Added patch (845095) to fix outline paint issues (DG);
 * 10-Mar-2004 : Numerous changes to enhance labelling (DG);
 * 31-Mar-2004 : Adjusted plot area when label generator is null (DG);
 * 08-Apr-2004 : Added flag to PiePlot class to control the treatment of null 
 *               values (DG);
 *               Added pieIndex to PieSectionEntity (DG);
 * 15-Nov-2004 : Removed creation of default tool tip generator (DG);
 * 16-Jun-2005 : Added default constructor (DG);
 * 
 */

package org.jfree.chart.plot;

import java.awt.AlphaComposite;
import java.awt.Color;
import java.awt.Composite;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics2D;
import java.awt.Paint;
import java.awt.Polygon;
import java.awt.Shape;
import java.awt.Stroke;
import java.awt.geom.Arc2D;
import java.awt.geom.Area;
import java.awt.geom.Ellipse2D;
import java.awt.geom.Point2D;
import java.awt.geom.Rectangle2D;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import org.jfree.chart.entity.EntityCollection;
import org.jfree.chart.entity.PieSectionEntity;
import org.jfree.chart.labels.PieToolTipGenerator;
import org.jfree.data.general.DatasetUtilities;
import org.jfree.data.general.PieDataset;
import org.jfree.ui.RectangleInsets;

/**
 * A plot that displays data in the form of a 3D pie chart, using data from
 * any class that implements the {@link PieDataset} interface.
 * <P>
 * Although this class extends {@link PiePlot}, it does not currently support
 * exploded sections.
 */
public class PiePlot3D extends PiePlot implements Serializable {

    /** For serialization. */
    private static final long serialVersionUID = 3408984188945161432L;
    
    /** The factor of the depth of the pie from the plot height */
    private double depthFactor = 0.2;

    /**
     * Creates a new instance with no dataset.
     */
    public PiePlot3D() {
        this(null);   
    }
    
    /**
     * Creates a pie chart with a three dimensional effect using the specified 
     * dataset.
     *
     * @param dataset  the dataset (<code>null</code> permitted).
     */
    public PiePlot3D(PieDataset dataset) {
        super(dataset);
        setCircular(false, false);
    }

    /**
     * Sets the pie depth as a percentage of the height of the plot area.
     *
     * @param factor  the depth factor (for example, 0.20 is twenty percent).
     */
    public void setDepthFactor(double factor) {
        this.depthFactor = factor;
    }

    /**
     * The depth factor for the chart.
     *
     * @return The depth factor.
     */
    public double getDepthFactor () {
        return this.depthFactor;
    }

    /**
     * Draws the plot on a Java 2D graphics device (such as the screen or a 
     * printer).  This method is called by the 
     * {@link org.jfree.chart.JFreeChart} class, you don't normally need 
     * to call it yourself.
     *
     * @param g2  the graphics device.
     * @param plotArea  the area within which the plot should be drawn.
     * @param anchor  the anchor point.
     * @param parentState  the state from the parent plot, if there is one.
     * @param info  collects info about the drawing 
     *              (<code>null</code> permitted).
     */
    public void draw(Graphics2D g2, Rectangle2D plotArea, Point2D anchor,
                     PlotState parentState,
                     PlotRenderingInfo info) {

        // adjust for insets...
        RectangleInsets insets = getInsets();
        insets.trim(plotArea);

        Rectangle2D originalPlotArea = (Rectangle2D) plotArea.clone();
        if (info != null) {
            info.setPlotArea(plotArea);
            info.setDataArea(plotArea);
        }

        Shape savedClip = g2.getClip();
        g2.clip(plotArea);

        // adjust the plot area by the interior spacing value
        double gapPercent = getInteriorGap();
        double labelPercent = 0.0;
        if (getLabelGenerator() != null) {
            labelPercent = getLabelGap() + getMaximumLabelWidth() 
                           + getLabelLinkMargin();   
        }
        double gapHorizontal = plotArea.getWidth() 
                               * (gapPercent + labelPercent);
        double gapVertical = plotArea.getHeight() * gapPercent;

        double linkX = plotArea.getX() + gapHorizontal / 2;
        double linkY = plotArea.getY() + gapVertical / 2;
        double linkW = plotArea.getWidth() - gapHorizontal;
        double linkH = plotArea.getHeight() - gapVertical;
        
        // make the link area a square if the pie chart is to be circular...
        if (isCircular()) { // is circular?
            double min = Math.min(linkW, linkH) / 2;
            linkX = (linkX + linkX + linkW) / 2 - min;
            linkY = (linkY + linkY + linkH) / 2 - min;
            linkW = 2 * min;
            linkH = 2 * min;
        }
        
        PiePlotState state = initialise(g2, plotArea, this, null, info);
        // the explode area defines the max circle/ellipse for the exploded pie 
        // sections.
        // it is defined by shrinking the linkArea by the linkMargin factor.
        double hh = linkW * getLabelLinkMargin();
        double vv = linkH * getLabelLinkMargin();
        Rectangle2D explodeArea = new Rectangle2D.Double(
            linkX + hh / 2.0, linkY + vv / 2.0, linkW - hh, linkH - vv
        );
       
        state.setExplodedPieArea(explodeArea);
        
        // the pie area defines the circle/ellipse for regular pie sections.
        // it is defined by shrinking the explodeArea by the explodeMargin 
        // factor. 
        double maximumExplodePercent = getMaximumExplodePercent();
        double percent = maximumExplodePercent / (1.0 + maximumExplodePercent);
        
        double h1 = explodeArea.getWidth() * percent;
        double v1 = explodeArea.getHeight() * percent;
        Rectangle2D pieArea = new Rectangle2D.Double(
            explodeArea.getX() + h1 / 2.0, explodeArea.getY() + v1 / 2.0,
            explodeArea.getWidth() - h1, explodeArea.getHeight() - v1
        );

        int depth = (int) (pieArea.getHeight() * this.depthFactor);
        // the link area defines the dog-leg point for the linking lines to 
        // the labels
        Rectangle2D linkArea = new Rectangle2D.Double(
            linkX, linkY, linkW, linkH - depth
        );
        state.setLinkArea(linkArea);   

        state.setPieArea(pieArea);
        state.setPieCenterX(pieArea.getCenterX());
        state.setPieCenterY(pieArea.getCenterY() - depth / 2.0);
        state.setPieWRadius(pieArea.getWidth() / 2.0);
        state.setPieHRadius((pieArea.getHeight() - depth) / 2.0);

        drawBackground(g2, plotArea);
        // get the data source - return if null;
        PieDataset dataset = getDataset();
        if (DatasetUtilities.isEmptyOrNull(getDataset())) {
            drawNoDataMessage(g2, plotArea);
            g2.setClip(savedClip);
            drawOutline(g2, plotArea);
            return;
        }

        // if too any elements
        if (dataset.getKeys().size() > plotArea.getWidth()) {
            String text = "Too many elements";
            Font sfont = new Font("dialog", Font.BOLD, 10);
            g2.setFont(sfont);
            FontMetrics fm = g2.getFontMetrics(sfont);
            int stringWidth = fm.stringWidth(text);

            g2.drawString(
                text, 
                (int) (plotArea.getX() + (plotArea.getWidth() - stringWidth) 
                        / 2),
                (int) (plotArea.getY() + (plotArea.getHeight() / 2))
            );
            return;
        }
        // if we are drawing a perfect circle, we need to readjust the top left
        // coordinates of the drawing area for the arcs to arrive at this
        // effect.
        if (isCircular()) {
            double min = Math.min(plotArea.getWidth(), 
                    plotArea.getHeight()) / 2;
            plotArea = new Rectangle2D.Double(
                plotArea.getCenterX() - min, plotArea.getCenterY() - min, 
                2 * min, 2 * min
            );
        }
        // get a list of keys...
        List sectionKeys = dataset.getKeys();

        if (sectionKeys.size() == 0) {
            return;
        }

        // establish the coordinates of the top left corner of the drawing area
        double arcX = pieArea.getX();
        double arcY = pieArea.getY();

        //g2.clip(clipArea);
        Composite originalComposite = g2.getComposite();
        g2.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 
                getForegroundAlpha()));

        double totalValue = DatasetUtilities.calculatePieDatasetTotal(dataset);
        double runningTotal = 0;
        if (depth < 0) {
            return;  // if depth is negative don't draw anything
        }

        ArrayList arcList = new ArrayList();
        Arc2D.Double arc;
        Paint paint;
        Paint outlinePaint;
        Stroke outlineStroke;

        Iterator iterator = sectionKeys.iterator();
        while (iterator.hasNext()) {

            Comparable currentKey = (Comparable) iterator.next();
            Number dataValue = dataset.getValue(currentKey);
            if (dataValue == null) {
                arcList.add(null);
                continue;
            }
            double value = dataValue.doubleValue();
            if (value <= 0) {
                arcList.add(null);
                continue;
            }
            double startAngle = getStartAngle();
            double direction = getDirection().getFactor();
            double angle1 = startAngle + (direction * (runningTotal * 360)) 
            / totalValue;
            double angle2 = startAngle + (direction * (runningTotal + value) 
                    * 360) / totalValue;
            if (Math.abs(angle2 - angle1) > getMinimumArcAngleToDraw()) {
                arcList.add(
                    new Arc2D.Double(
                        arcX, arcY + depth, pieArea.getWidth(), 
                        pieArea.getHeight() - depth,
                        angle1, angle2 - angle1, Arc2D.PIE
                    )
                );
            }
            else {
                arcList.add(null);
            }
            runningTotal += value;
        }

        Shape oldClip = g2.getClip();

        Ellipse2D top = new Ellipse2D.Double(
            pieArea.getX(), pieArea.getY(), pieArea.getWidth(), 
            pieArea.getHeight() - depth
        );

        Ellipse2D bottom = new Ellipse2D.Double(
            pieArea.getX(), pieArea.getY() + depth, pieArea.getWidth(), 
            pieArea.getHeight() - depth
        );

        Rectangle2D lower = new Rectangle2D.Double(
            top.getX(), top.getCenterY(), pieArea.getWidth(), 
            bottom.getMaxY() - top.getCenterY()
        );

        Rectangle2D upper = new Rectangle2D.Double(
            pieArea.getX(), top.getY(), pieArea.getWidth(),
            bottom.getCenterY() - top.getY()
        );

        Area a = new Area(top);
        a.add(new Area(lower));
        Area b = new Area(bottom);
        b.add(new Area(upper));
        Area pie = new Area(a);
        pie.intersect(b);

        Area front = new Area(pie);
        front.subtract(new Area(top));

        Area back = new Area(pie);
        back.subtract(new Area(bottom));

        // draw the bottom circle
        int[] xs;
        int[] ys;
        outlinePaint = getSectionOutlinePaint(0);
        arc = new Arc2D.Double(
            arcX, arcY + depth, pieArea.getWidth(), pieArea.getHeight() - depth,
            0, 360, Arc2D.PIE
        );

        int categoryCount = arcList.size();
        for (int categoryIndex = 0; categoryIndex < categoryCount; 
             categoryIndex++) {
            arc = (Arc2D.Double) arcList.get(categoryIndex);
            if (arc == null) {
                continue;
            }
            paint = getSectionPaint(categoryIndex);
            outlinePaint = getSectionOutlinePaint(categoryIndex);
            outlineStroke = getSectionOutlineStroke(categoryIndex);
            g2.setPaint(paint);
            g2.fill(arc);
            g2.setPaint(outlinePaint);
            g2.setStroke(outlineStroke);
            g2.draw(arc);
            g2.setPaint(paint);

            Point2D p1 = arc.getStartPoint();

            // draw the height
            xs = new int[] {
                (int) arc.getCenterX(), (int) arc.getCenterX(),
                (int) p1.getX(), (int) p1.getX() 
            };
            ys = new int[] {
                (int) arc.getCenterY(), (int) arc.getCenterY() - depth,
                (int) p1.getY() - depth, (int) p1.getY() 
            };
            Polygon polygon = new Polygon(xs, ys, 4);
            g2.setPaint(java.awt.Color.lightGray);
            g2.fill(polygon);
            g2.setPaint(outlinePaint);
            g2.setStroke(outlineStroke);
            g2.draw(polygon);
            g2.setPaint(paint);

        }

        g2.setPaint(Color.gray);
        g2.fill(back);
        g2.fill(front);

        // cycle through once drawing only the sides at the back...
        int cat = 0;
        iterator = arcList.iterator();
        while (iterator.hasNext()) {
            Arc2D segment = (Arc2D) iterator.next();
            if (segment != null) {
                paint = getSectionPaint(cat);
                outlinePaint = getSectionOutlinePaint(cat);
                outlineStroke = getSectionOutlineStroke(cat);
                drawSide(
                    g2, pieArea, segment, front, back, paint, 
                    outlinePaint, outlineStroke, 
                    false, true
                );
            }
            cat++;
        }

        // cycle through again drawing only the sides at the front...
        cat = 0;
        iterator = arcList.iterator();
        while (iterator.hasNext()) {
            Arc2D segment = (Arc2D) iterator.next();
            if (segment != null) {
                paint = getSectionPaint(cat);
                outlinePaint = getSectionOutlinePaint(cat);
                outlineStroke = getSectionOutlineStroke(cat);
                drawSide(
                    g2, pieArea, segment, front, back, paint, 
                    outlinePaint, outlineStroke, 
                    true, false
                );
            }
            cat++;
        }

        g2.setClip(oldClip);

        // draw the sections at the top of the pie (and set up tooltips)...
        Arc2D upperArc;
        for (int sectionIndex = 0; sectionIndex < categoryCount; 
             sectionIndex++) {
            arc = (Arc2D.Double) arcList.get(sectionIndex);
            if (arc == null) {
                continue;
            }
            upperArc = new Arc2D.Double(
                arcX, arcY, pieArea.getWidth(), pieArea.getHeight() - depth,
                arc.getAngleStart(), arc.getAngleExtent(), Arc2D.PIE
            );
            
            paint = getSectionPaint(sectionIndex);
            outlinePaint = getSectionOutlinePaint(sectionIndex);
            outlineStroke = getSectionOutlineStroke(sectionIndex);
            g2.setPaint(paint);
            g2.fill(upperArc);
            g2.setStroke(outlineStroke);
            g2.setPaint(outlinePaint);
            g2.draw(upperArc);

           // add a tooltip for the section...
            Comparable currentKey = (Comparable) sectionKeys.get(sectionIndex);
            if (info != null) {
                EntityCollection entities 
                    = info.getOwner().getEntityCollection();
                if (entities != null) {
                    String tip = null;
                    PieToolTipGenerator tipster = getToolTipGenerator();
                    if (tipster != null) {
                        // @mgs: using the method's return value was missing 
                        tip = tipster.generateToolTip(dataset, currentKey);
                    }
                    String url = null;
                    if (getURLGenerator() != null) {
                        url = getURLGenerator().generateURL(dataset, currentKey,
                                getPieIndex());
                    }
                    PieSectionEntity entity = new PieSectionEntity(
                        upperArc, dataset, getPieIndex(), sectionIndex, 
                        currentKey, tip, url
                    );
                    entities.add(entity);
                }
            }
            List keys = dataset.getKeys();
            Rectangle2D adjustedPlotArea = new Rectangle2D.Double(
                originalPlotArea.getX(), originalPlotArea.getY(), 
                originalPlotArea.getWidth(), 
                originalPlotArea.getHeight() - depth
            );
            drawLabels(g2, keys, totalValue, adjustedPlotArea, linkArea, state);
        }

        g2.setClip(savedClip);
        g2.setComposite(originalComposite);
        drawOutline(g2, originalPlotArea);

    }

    /**
     * Draws the side of a pie section.
     *
     * @param g2  the graphics device.
     * @param plotArea  the plot area.
     * @param arc  the arc.
     * @param front  the front of the pie.
     * @param back  the back of the pie.
     * @param paint  the color.
     * @param outlinePaint  the outline paint.
     * @param outlineStroke  the outline stroke.
     * @param drawFront  draw the front?
     * @param drawBack  draw the back?
     */
    protected void drawSide(Graphics2D g2,
                            Rectangle2D plotArea, 
                            Arc2D arc, 
                            Area front, 
                            Area back,
                            Paint paint, 
                            Paint outlinePaint,
                            Stroke outlineStroke,
                            boolean drawFront, 
                            boolean drawBack) {

        double start = arc.getAngleStart();
        double extent = arc.getAngleExtent();
        double end = start + extent;

        g2.setStroke(outlineStroke);
        
        // for CLOCKWISE charts, the extent will be negative...
        if (extent < 0.0) {

            if (isAngleAtFront(start)) {  // start at front

                if (!isAngleAtBack(end)) {

                    if (extent > -180.0) {  // the segment is entirely at the 
                                            // front of the chart
                        if (drawFront) {
                            Area side = new Area(
                                new Rectangle2D.Double(
                                    arc.getEndPoint().getX(), plotArea.getY(),
                                    arc.getStartPoint().getX() 
                                    - arc.getEndPoint().getX(),
                                    plotArea.getHeight()
                                )
                            );
                            side.intersect(front);
                            g2.setPaint(paint);
                            g2.fill(side);
                            g2.setPaint(outlinePaint);
                            g2.draw(side);
                        }
                    }
                    else {  // the segment starts at the front, and wraps all 
                            // the way around
                            // the back and finishes at the front again
                        Area side1 = new Area(
                            new Rectangle2D.Double(
                                plotArea.getX(), plotArea.getY(),
                                arc.getStartPoint().getX() - plotArea.getX(), 
                                plotArea.getHeight()
                            )
                        );
                        side1.intersect(front);

                        Area side2 = new Area(
                            new Rectangle2D.Double(
                                arc.getEndPoint().getX(), plotArea.getY(),
                                plotArea.getMaxX() - arc.getEndPoint().getX(),
                                plotArea.getHeight()
                            )
                        );

                        side2.intersect(front);
                        g2.setPaint(paint);
                        if (drawFront) {
                            g2.fill(side1);
                            g2.fill(side2);
                        }

                        if (drawBack) {
                            g2.fill(back);
                        }

                        g2.setPaint(outlinePaint);
                        if (drawFront) {
                            g2.draw(side1);
                            g2.draw(side2);
                        }

                        if (drawBack) {
                            g2.draw(back);
                        }

                    }
                }
                else {  // starts at the front, finishes at the back (going 
                        // around the left side)

                    if (drawBack) {
                        Area side2 = new Area(
                            new Rectangle2D.Double(
                                plotArea.getX(), plotArea.getY(),
                                arc.getEndPoint().getX() - plotArea.getX(), 
                                plotArea.getHeight()
                            )
                        );
                        side2.intersect(back);
                        g2.setPaint(paint);
                        g2.fill(side2);
                        g2.setPaint(outlinePaint);
                        g2.draw(side2);
                    }

                    if (drawFront) {
                        Area side1 = new Area(
                            new Rectangle2D.Double(
                                plotArea.getX(), plotArea.getY(),
                                arc.getStartPoint().getX() - plotArea.getX(),
                                plotArea.getHeight()
                            )
                        );
                        side1.intersect(front);
                        g2.setPaint(paint);
                        g2.fill(side1);
                        g2.setPaint(outlinePaint);
                        g2.draw(side1);
                    }
                }
            }
            else {  // the segment starts at the back (still extending 
                    // CLOCKWISE)

                if (!isAngleAtFront(end)) {
                    if (extent > -180.0) {  // whole segment stays at the back
                        if (drawBack) {
                            Area side = new Area(
                                new Rectangle2D.Double(
                                    arc.getStartPoint().getX(), plotArea.getY(),
                                    arc.getEndPoint().getX() 
                                    - arc.getStartPoint().getX(),
                                    plotArea.getHeight()
                                )
                            );
                            side.intersect(back);
                            g2.setPaint(paint);
                            g2.fill(side);
                            g2.setPaint(outlinePaint);
                            g2.draw(side);
                        }
                    }
                    else {  // starts at the back, wraps around front, and 
                            // finishes at back again
                        Area side1 = new Area(
                            new Rectangle2D.Double(
                                arc.getStartPoint().getX(), plotArea.getY(),
                                plotArea.getMaxX() - arc.getStartPoint().getX(),
                                plotArea.getHeight()
                            )
                        );
                        side1.intersect(back);

                        Area side2 = new Area(
                            new Rectangle2D.Double(
                                plotArea.getX(), plotArea.getY(),
                                arc.getEndPoint().getX() - plotArea.getX(),
                                plotArea.getHeight()
                            )
                        );

                        side2.intersect(back);

                        g2.setPaint(paint);
                        if (drawBack) {
                            g2.fill(side1);
                            g2.fill(side2);
                        }

                        if (drawFront) {
                            g2.fill(front);
                        }

                        g2.setPaint(outlinePaint);
                        if (drawBack) {
                            g2.draw(side1);
                            g2.draw(side2);
                        }

                        if (drawFront) {
                            g2.draw(front);
                        }

                    }
                }
                else {  // starts at back, finishes at front (CLOCKWISE)

                    if (drawBack) {
                        Area side1 = new Area(
                            new Rectangle2D.Double(
                                arc.getStartPoint().getX(), plotArea.getY(),
                                plotArea.getMaxX() - arc.getStartPoint().getX(),
                                plotArea.getHeight()
                            )
                        );
                        side1.intersect(back);
                        g2.setPaint(paint);
                        g2.fill(side1);
                        g2.setPaint(outlinePaint);
                        g2.draw(side1);
                    }

                    if (drawFront) {
                        Area side2 = new Area(
                            new Rectangle2D.Double(
                                arc.getEndPoint().getX(), plotArea.getY(),
                                plotArea.getMaxX() - arc.getEndPoint().getX(),
                                plotArea.getHeight()
                            )
                        );
                        side2.intersect(front);
                        g2.setPaint(paint);
                        g2.fill(side2);
                        g2.setPaint(outlinePaint);
                        g2.draw(side2);
                    }

                }
            }
        }
        else if (extent > 0.0) {  // the pie sections are arranged ANTICLOCKWISE

            if (isAngleAtFront(start)) {  // segment starts at the front

                if (!isAngleAtBack(end)) {  // and finishes at the front

                    if (extent < 180.0) {  // segment only occupies the front
                        if (drawFront) {
                            Area side = new Area(
                                new Rectangle2D.Double(
                                    arc.getStartPoint().getX(), plotArea.getY(),
                                    arc.getEndPoint().getX() 
                                    - arc.getStartPoint().getX(),
                                    plotArea.getHeight()
                                )
                            );
                            side.intersect(front);
                            g2.setPaint(paint);
                            g2.fill(side);
                            g2.setPaint(outlinePaint);
                            g2.draw(side);
                        }
                    }
                    else {  // segments wraps right around the back...
                        Area side1 = new Area(
                            new Rectangle2D.Double(
                                arc.getStartPoint().getX(), plotArea.getY(),
                                plotArea.getMaxX() - arc.getStartPoint().getX(),
                                plotArea.getHeight()
                            )
                        );
                        side1.intersect(front);

                        Area side2 = new Area(
                            new Rectangle2D.Double(
                                plotArea.getX(), plotArea.getY(),
                                arc.getEndPoint().getX() - plotArea.getX(),
                                plotArea.getHeight()
                            )
                        );
                        side2.intersect(front);

                        g2.setPaint(paint);
                        if (drawFront) {
                            g2.fill(side1);
                            g2.fill(side2);
                        }

                        if (drawBack) {
                            g2.fill(back);
                        }

                        g2.setPaint(outlinePaint);
                        if (drawFront) {
                            g2.draw(side1);
                            g2.draw(side2);
                        }

                        if (drawBack) {
                            g2.draw(back);
                        }

                    }
                }
                else {  // segments starts at front and finishes at back...
                    if (drawBack) {
                        Area side2 = new Area(
                            new Rectangle2D.Double(
                                arc.getEndPoint().getX(), plotArea.getY(),
                                plotArea.getMaxX() - arc.getEndPoint().getX(),
                                plotArea.getHeight()
                            )
                        );
                        side2.intersect(back);
                        g2.setPaint(paint);
                        g2.fill(side2);
                        g2.setPaint(outlinePaint);
                        g2.draw(side2);
                    }

                    if (drawFront) {
                        Area side1 = new Area(
                            new Rectangle2D.Double(
                                arc.getStartPoint().getX(), plotArea.getY(),
                                plotArea.getMaxX() - arc.getStartPoint().getX(),
                                plotArea.getHeight()
                            )
                        );
                        side1.intersect(front);
                        g2.setPaint(paint);
                        g2.fill(side1);
                        g2.setPaint(outlinePaint);
                        g2.draw(side1);
                    }
                }
            }
            else {  // segment starts at back

                if (!isAngleAtFront(end)) {
                    if (extent < 180.0) {  // and finishes at back
                        if (drawBack) {
                            Area side = new Area(
                                new Rectangle2D.Double(
                                    arc.getEndPoint().getX(), plotArea.getY(),
                                    arc.getStartPoint().getX() 
                                    - arc.getEndPoint().getX(),
                                    plotArea.getHeight()
                                )
                            );
                            side.intersect(back);
                            g2.setPaint(paint);
                            g2.fill(side);
                            g2.setPaint(outlinePaint);
                            g2.draw(side);
                        }
                    }
                    else {  // starts at back and wraps right around to the 
                            // back again
                        Area side1 = new Area(
                            new Rectangle2D.Double(
                                arc.getStartPoint().getX(), plotArea.getY(),
                                plotArea.getX() - arc.getStartPoint().getX(),
                                plotArea.getHeight()
                            )
                        );
                        side1.intersect(back);

                        Area side2 = new Area(
                            new Rectangle2D.Double(
                                arc.getEndPoint().getX(), plotArea.getY(),
                                plotArea.getMaxX() - arc.getEndPoint().getX(),
                                plotArea.getHeight()
                            )
                        );
                        side2.intersect(back);

                        g2.setPaint(paint);
                        if (drawBack) {
                            g2.fill(side1);
                            g2.fill(side2);
                        }

                        if (drawFront) {
                            g2.fill(front);
                        }

                        g2.setPaint(outlinePaint);
                        if (drawBack) {
                            g2.draw(side1);
                            g2.draw(side2);
                        }

                        if (drawFront) {
                            g2.draw(front);
                        }

                    }
                }
                else {  // starts at the back and finishes at the front 
                        // (wrapping the left side)
                    if (drawBack) {
                        Area side1 = new Area(
                            new Rectangle2D.Double(
                                plotArea.getX(), plotArea.getY(),
                                arc.getStartPoint().getX() - plotArea.getX(),
                                plotArea.getHeight()
                            )
                        );
                        side1.intersect(back);
                        g2.setPaint(paint);
                        g2.fill(side1);
                        g2.setPaint(outlinePaint);
                        g2.draw(side1);
                    }

                    if (drawFront) {
                        Area side2 = new Area(
                            new Rectangle2D.Double(
                                plotArea.getX(), plotArea.getY(),
                                arc.getEndPoint().getX() - plotArea.getX(),
                                plotArea.getHeight()
                            )
                        );
                        side2.intersect(front);
                        g2.setPaint(paint);
                        g2.fill(side2);
                        g2.setPaint(outlinePaint);
                        g2.draw(side2);
                    }
                }
            }

        }

    }

    /**
     * Returns a short string describing the type of plot.
     *
     * @return <i>Pie 3D Plot</i>.
     */
    public String getPlotType () {
        return localizationResources.getString("Pie_3D_Plot");
    }

    /**
     * A utility method that returns true if the angle represents a point at 
     * the front of the 3D pie chart.  0 - 180 degrees is the back, 180 - 360 
     * is the front.
     *
     * @param angle  the angle.
     *
     * @return A boolean.
     */
    private boolean isAngleAtFront(double angle) {
        return (Math.sin(Math.toRadians(angle)) < 0.0);
    }

    /**
     * A utility method that returns true if the angle represents a point at 
     * the back of the 3D pie chart.  0 - 180 degrees is the back, 180 - 360 
     * is the front.
     *
     * @param angle  the angle.
     *
     * @return <code>true</code> if the angle is at the back of the pie.
     */
    private boolean isAngleAtBack(double angle) {
        return (Math.sin(Math.toRadians(angle)) > 0.0);
    }

}
